In television systems, the ability to view a channel guide or menu is a popular feature. The channel guide allows a user to review program titles and content before selecting a channel. In analog television systems, a channel was dedicated as a television guide channel that would list the contents of each channel, but was not interactive. However, in digital systems, users are presented with an interactive television guide which is dynamically updated, and allows a user to review additional programming information (such as program descriptions etc.), and switch between channels. The interactive television guide receives signals from all the channels and generates a channel list including the programming information. However, this typically requires increased bandwidth and high power consumption when placed in a mobile device.
Because battery life is an important feature in mobile devices, power management is utilized to minimize the power consumption of the overall system, which can extend battery life and prevent overheating.
For example, DVB-H implements multiprotocol encapsulation (MPE), MPE forward error correction (MPE-FEC), and time slicing as a part of its power management scheme for mobile devices.
Time slicing comprises the transmission of data traffic in bursts followed by periods of no transmissions. The burst transmissions are referred to as time slices. In order to reduce the power consumption of the DVB-H handset, the DVB-H handset can shut down the receiver for the duration between the time slices.
In a typical DVB-H communication, multiple input streams are received by different sources as individual elementary streams. The input streams are multiplexed according to a selected time slicing method. MPE-FEC coding, which provides an additional layer of error correction, is performed separately for each individual elementary stream. The system then performs MPE encapsulation of the data packets and embeds them into a transport stream.
In addition to receiving single stream transmissions, the DVB-H Guidelines also support the reception of multiple elementary streams embedded in the same burst as well as multiple services embedded in the single elementary stream. There are three scenarios for transmitting multiple element streams in DVB-H, as described further below. To illustrate the design of multiple stream power management, an example using two element streams, is shown for all three scenarios.
FIG. 1 is a graph showing the power management of a DVB-H handset receiving multiple channels transmitted on concurrent streams.
FIG. 2 is a graph showing the power management of a DVB-H handset receiving multiple channels where the services are located on contiguous streams.
FIG. 3 is a graph showing the power management of a DVB-H handset receiving multiple channels where the services are located on isolated streams.
A method for fast stream switching for the multi-stream and single stream applications using dynamic power management is desired.